The first departure controller 's experience led him to believe that a Beech 1900D on departure from runway 08 right, given a vector of 010 degrees when through 3000 feet, would easily achieve the altitude levels necessary to meet the MVA to the north of Vancouver. In this occurrence, aircraft climb performance varied from what was expected by the controller. The need to attend to a separation problem to the south of Vancouver, an area designed to be controlled by another controller, diverted the first departure controller's attention for a short time. The distraction was long enough to allow the aircraft's climb rate and high forward speed to place it inside the boundary of the 7000-foot MVA before the first departure controller noticed it. The perceived need to quickly relieve the first departure controller led to a hastily performed transfer of position responsibility briefing which may not have been sufficiently accurate to ensure that the relieving controller was fully aware of the dynamic control situation. The speedy replacement may have encouraged the controllers to ignore the use of the transfer of position responsibility checklist. The lack of (or inaccurate) altitude information on the flight progress strip, together with the Mode C altitude readout showing the aircraft above 8000 feet and the lack of an adequate change of position responsibility briefing, may have contributed to the belief of the second departure controller that the Beech 1900D was established in a climb. The time at which the flight progress strip was annotated with altitude information, or the reason(s) some of that information was inaccurate, could not be determined. When the second departure controller cleared the Beech 1900D to climb to 11 000 feet only two miles from the 9000-foot MVA boundary, he expected the aircraft to be able to meet the altitude requirements. Again, traffic to the south distracted the controller, and he was not aware that the Beech 1900D had penetrated the 9000-foot MVA below the required altitude. The practice of vectoring departures off runway 08 directly toward the high terrain to the north of Vancouver in order to expedite traffic movements requires that controllers pay careful attention to the climb performance of those aircraft. The need to control the climb rate of those northbound departures to keep them above the steadily climbing MVA contours, yet below the arrivals on the downwind leg at 10 000 feet, places an additional onus on controllers to be particularly vigilant. The additional duties of the south departure controller position inevitably divert attention away from the climbing northbound traffic, impose additional distractions during this particularly critical phase of flight, and increase the risk of an ATS incident.Analysis The first departure controller 's experience led him to believe that a Beech 1900D on departure from runway 08 right, given a vector of 010 degrees when through 3000 feet, would easily achieve the altitude levels necessary to meet the MVA to the north of Vancouver. In this occurrence, aircraft climb performance varied from what was expected by the controller. The need to attend to a separation problem to the south of Vancouver, an area designed to be controlled by another controller, diverted the first departure controller's attention for a short time. The distraction was long enough to allow the aircraft's climb rate and high forward speed to place it inside the boundary of the 7000-foot MVA before the first departure controller noticed it. The perceived need to quickly relieve the first departure controller led to a hastily performed transfer of position responsibility briefing which may not have been sufficiently accurate to ensure that the relieving controller was fully aware of the dynamic control situation. The speedy replacement may have encouraged the controllers to ignore the use of the transfer of position responsibility checklist. The lack of (or inaccurate) altitude information on the flight progress strip, together with the Mode C altitude readout showing the aircraft above 8000 feet and the lack of an adequate change of position responsibility briefing, may have contributed to the belief of the second departure controller that the Beech 1900D was established in a climb. The time at which the flight progress strip was annotated with altitude information, or the reason(s) some of that information was inaccurate, could not be determined. When the second departure controller cleared the Beech 1900D to climb to 11 000 feet only two miles from the 9000-foot MVA boundary, he expected the aircraft to be able to meet the altitude requirements. Again, traffic to the south distracted the controller, and he was not aware that the Beech 1900D had penetrated the 9000-foot MVA below the required altitude. The practice of vectoring departures off runway 08 directly toward the high terrain to the north of Vancouver in order to expedite traffic movements requires that controllers pay careful attention to the climb performance of those aircraft. The need to control the climb rate of those northbound departures to keep them above the steadily climbing MVA contours, yet below the arrivals on the downwind leg at 10 000 feet, places an additional onus on controllers to be particularly vigilant. The additional duties of the south departure controller position inevitably divert attention away from the climbing northbound traffic, impose additional distractions during this particularly critical phase of flight, and increase the risk of an ATS incident. Traffic within the south departure sector distracted both departure controllers from their duty of ensuring terrain clearance for an aircraft on radar vectors in the north departure sector. A standard change of position responsibility briefing was not conducted adequately when the second departure controller quickly took over from the first. Erroneous altitude information was entered on the flight progress strip. The flight data strip was not marked and updated in accordance with directives. The climb performance of the Beech 1900D differed from the departure controllers' expectations.Findings as to Causes and Contributing Factors Traffic within the south departure sector distracted both departure controllers from their duty of ensuring terrain clearance for an aircraft on radar vectors in the north departure sector. A standard change of position responsibility briefing was not conducted adequately when the second departure controller quickly took over from the first. Erroneous altitude information was entered on the flight progress strip. The flight data strip was not marked and updated in accordance with directives. The climb performance of the Beech 1900D differed from the departure controllers' expectations. The pilot of the Beech 1900D was not made aware that, while on radar vectors, the aircraft had twice been permitted to enter airspace below the minimum IFR altitude. The controllers did not use the recommended MANOPS phraseology to warn the pilot that the aircraft was below the minimum IFR altitude. The POCO ONE SID requires northbound propeller-driven aircraft to turn toward high terrain soon after take-off in order to expedite other departures.Findings as to Risk The pilot of the Beech 1900D was not made aware that, while on radar vectors, the aircraft had twice been permitted to enter airspace below the minimum IFR altitude. The controllers did not use the recommended MANOPS phraseology to warn the pilot that the aircraft was below the minimum IFR altitude. The POCO ONE SID requires northbound propeller-driven aircraft to turn toward high terrain soon after take-off in order to expedite other departures. The second incursion of the Beech 1900D into a 9000-foot MVA sector below the minimum IFR altitude was not detected until radar tapes were reviewed the day after the occurrence.Other Findings The second incursion of the Beech 1900D into a 9000-foot MVA sector below the minimum IFR altitude was not detected until radar tapes were reviewed the day after the occurrence. Immediately following this occurrence, Vancouver ACC and tower management issued direction to controllers cancelling the POCO ONE SID until a review of the SID and all associated procedures could be completed. Tower controllers will ensure that propeller aircraft departing runway 08 right northbound will be assigned runway heading and will not be turned immediately toward the higher terrain to the north of Vancouver.Safety Action Immediately following this occurrence, Vancouver ACC and tower management issued direction to controllers cancelling the POCO ONE SID until a review of the SID and all associated procedures could be completed. Tower controllers will ensure that propeller aircraft departing runway 08 right northbound will be assigned runway heading and will not be turned immediately toward the higher terrain to the north of Vancouver.